Apparatus and method for guiding a tool along a path on a surface

ABSTRACT

Tool guiding apparatus for guiding a tool along a path on a surface to be processed, said apparatus comprising at least one path-defining means adapted to be attached to the surface, automatic tool actuating means adapted to advance the tool along the path. Wherein the automatic tool actuation means comprises a flexible force-transferring element comprising a first end and a second end, the first end being attached to the automatic tool actuation means and the second end being attached to the tool.

FIELD OF THE INVENTION

The present invention relates to an apparatus for guiding a tool along apath, in particular to an apparatus for cutting a compound between awindscreen and an automobile. Furthermore, the invention relates to amethod of cutting a path along a predetermined line, in particular to amethod for guiding a knife along a compound between a windscreen and anautomobile.

BACKGROUND OF THE INVENTION

Windscreens are glued to the automobile by means of a strong compound orglue. For many years car manufacturers have improved the glue so as toensure a strong and binding connection. One reason for this is thatwindscreens today are load-bearing elements. Unfortunately, thewindscreens need to be replaced from time to time. This is due to holesor scratches made by thrown-up pebbles. Concurrently with the improvedglue or compound the windscreens are becoming harder to remove. Threegeneral principles for removing the glue are known. The three principlesare oscillating knives, cold knives and cutting wires.

The use of each of three principles provide working conditions whichover time may result in working related injuries. For the user theoscillating knives are the easiest to use as the force needed to beapplied is low as the oscillating knives cut their way through the glue.However, over time the vibrating nature of the oscillating knife maycause Raynaud Syndrome. Furthermore, the use of the oscillating kniferequires that the user wear a hearing protection. As such hearingprotecting must be taking on and off several times during the day, manyusers omit using the hearing protection. Over time this results inhearing damages.

Cold knives and the cutting wires require a considerable amount of forceto use and as the working position of the user is awkward the use ofthese tools over time may result in back injuries. U.S. Pat. No.3,924,327 discloses a solution to this problem by providing a powersupplied force transferring means e.g. an air-hammer. Like theoscillating knife the force transferring means has a vibrating naturewhich may over time result in Raynaud Syndrome.

U.S. Pat. No. 4,819,531 discloses a cutting tool comprising a blade anda winch assembly. A wire connected to the winch assembly is secured to apart of the automobile and thus the user may only steer the blade withone hand as the other must be used to operate the winch.

Furthermore, manipulation of the winch lever transmits force to theblade. As the force constantly changes direction and intensity thesteering of the blade is complicated even further.

WO 86/07017 discloses an apparatus comprising a cutting wire fordismounting a windscreen, where the cutting wire is arranged along theglue joint of the windscreen. The cutting wire of this apparatus isdrawn by a drawing device, which may incorporate a motor. The apparatuscomprises a movable guide for guiding the cutting wire. The cutting wiremust be strong enough to withstand the considerable force necessary tocut the glue joint of the windscreen, which means that the wire musthave a relatively large cross-section. To be able to cut the glue joint,however, the wire must have a very small cross-section, and it isdifficult to achieve a compromise between these conflictingrequirements. Further there is a risk that the cutting wire willdisengage from the glue joint, especially at the corners of thewindscreen, with potential risk of damage to the apparatus, the vehicleor even injury to the operator of the apparatus. Further it is notpossible to guide the cutting wire with any kind of precision in theglue joint, hence there is a risk of damaging inter alia the paint ofthe vehicle. Furthermore the initial step of arranging the cutting wirethrough and around the glue joint is laborious. Finally the apparatusmust be installed within the cabin of the vehicle where there is alimited working space which renders the installation difficult. Withmodern cars having very inclined windscreens, it may be almostimpossible to have access to the lower inside corners.

DESCRIPTION OF THE INVENTION

It is an object of the present invention to provide an apparatus and amethod which overcome the above mentioned disadvantages. Thus thepresent invention relates to a tool guiding apparatus for guiding a toolalong a path on a surface to be processed, said apparatus comprising:

at least one path-defining means adapted to be attached to the surface,automatic tool actuation means adapted to advance the tool along thepath, wherein the automatic tool actuation means comprises a flexibleforce-transferring element comprising a first end and a second end, thefirst end being attached to the automatic tool actuation means and thesecond end being attached to the tool.

The tool may be guided along a plurality of straight lines but couldalso be guided along curves such as semicircles or a s-curve or ahyperbola or any other curve. The path may be a combination of curvesand straight lines. The path defining means may be attached to thesurface to be processed but could also be attached to a surface adjacentto the surface to be processed. E.g. the path defining means may beattached to a windscreen so as to enable cutting of glue between awindscreen and the frame of a car. The path defining means may also beattached to a panel or a plate to be cut. At least a part of the pathdefining means may be shaped so as to follow at least a part of thecurve to be followed by the tool. The path defining means may comprise astructure such as a frame which is adapted to guide the tool along thepath to be followed.

By automatic tool actuation means is meant means which advances the toolwithout application of force by the user during operation. Thus the usermay devote force and attention to steering and guiding, resulting inimproved quality of the work done by the tool. The automatic toolactuation means may be means which during operation requires externalsupply of energy such as fuel or electricity, but the means may also bemeans which must be charged with energy prior to use. E.g. the means maybe a spring such as a helical spring which must be turned prior to useof the device so as to be able to transfer energy to the tool.

The first end of the flexible force transferring element may be attachedto a wheel on the automatic tool actuation means, which is adapted toreel in the flexible force-transferring element. The force-transferringelement may be a wire or a chain or a belt. The flexibleforce-transferring element may be flexible in only one plane but couldalso be flexible in two planes or in any direction. If the flexibleforce-transferring element is flexible in two planes, the two planes maybe substantially perpendicular to each other.

The path-defining means may be adapted to engage at least a part of theflexible force-transferring element. By engaging the force-transferringelement the path-defining means defines the path which the tool is tofollow. The path defining means may be a curved surface along which theforce-transferring element may be provided. As an example the pathdefining means may be a semi-circular surface along which a belt isprovided. The belt and the surface may have low frictional properties soas to enable pulling the belt along the surface. If the forcetransferring element is a chain the path-defining means may be providedwith a toothed wheel which engages the chain. The toothed wheel may makeit possible to pull the chain and may steer the chain in a directionsubstantially parallel to the axis of rotation of the wheel.

In an embodiment the path-defining means may comprise a wheel adapted toengage at least a part of the force-transferring element. If theforce-transferring element is a belt, the wheel may be provided withflanges on each side of the wheel so as to steer the belt in a directionsubstantially parallel to the axis of rotation of the wheel. In anembodiment the wheel and the force transferring element is provided withmagnets so as to steer the belt in a direction substantially parallel tothe axis of rotation of the wheel.

Furthermore, the automatic tool actuation means may be adapted to beattached to the surface to be processed. Both the path defining meansand the force transferring element may, at the same time, be attached tothe surface to be processes or a surface adjacent to the surface to beprocessed. In an embodiment the path defining means may be attached tothe windscreen while the actuation means is attached to the samewindscreen. Alternatively the path defining means may be attached to theroof or a side of a car while the actuation means may be attached to thewindscreen or vice versa. The automatic actuation means may be attachedto a wall or a ceiling or a structure placed adjacent to the item to beprocessed. As an example the actuation means may be attached to a frame.The frame may be provided with wheels so that it may be moved around ine.g. a workshop.

At least one of the automatic tool actuation means and the at least onepath-defining means may comprise at least one vacuum cup and/or anothermeans for attachment to the surface to be processed such as magnetsprovided on each side of the surface to be processed. In someembodiments at least a part of the path-defining means or the automatictool actuation means is attached to the surface to by processed by meansof glue or screws or nails or welding or Velcro® tape.

In an embodiment the path defining means and/or the actuation means mayeach be provided with one vacuum cup, but could also be provided with aplurality of vacuum cups such as two or three or four or five or six orseven or eight or nine or ten. The diameter of the vacuum cups may be 2cm or 3 cm or 4 cm or 5 cm or 6 cm or 7 cm or 8 cm or 9 cm or 10 cm or11 cm or 12 cm or 13 cm or 14 cm or 15 cm or 16 cm or 17 cm or 18 cm or19 cm or 20 cm or 25 cm or 30 cm or 35 cm or 45 cm or 50 cm. If the pathdefining means and/or the actuation means is provided with more than onevacuum cup, said cups may be provided in different sizes. The vacuumcup(s) may be connected to a vacuum pump for easy mounting of the vacuumcup(s) on a surface.

The tool may comprise a knife with a cutting edge such as a cold-knife.Furthermore, the tool to be guided may be a saw e.g. a compass saw or acircular saw, but could also be a shuffle sander or an eccentric sanderor a machine for polishing or an welding apparatus or a blowtorch or adiamond cutter or a laser cutter or a painting device or an oscillatingknife or a plate shears such as automated plate shears.

The knife may be provided with means for generating heat so as toelevate the temperature of the cutting blade. The knife may be providedwith a plurality of blades such a two or three or four or five. Aplurality of knives may also be provided. The blade(s) of the knife(s)may be changeable so that the same fixture may be used with differentblades of the same kind or blades of different types such as straightblades, serrated blades, curved blades etc. The blades or the knife maybe provided with means for applying a friction-reducing means to thecutting zone. E.g. in one embodiment the blade is provided with holesthrough which liquid is applied. The liquid may be oil or sulphone orsoap or water.

At least a part of the cutting edge may extend in a direction transverseto a line defined by at least a part of the force-transferring element.The line may be defined by that part of the line, which is closest tothe knife or tool. The cutting edge may extend in a directionsubstantially perpendicular to the said line.

In one embodiment the vacuum cup and the wheel may be interconnected bya moment arm. Thus the moment arm in one end may be provided with avacuum cup and in the other end may be provided with the wheel. Themoment arm may also be provided with a plurality of vacuum cups e.g. sothat the arm in one end is provided with the wheel and along the arm isprovided with a plurality of cups such as two or three or four or fiveor ten. The path defining means may also be provided with a plurality ofmoment arms each comprising at least one vacuum cup. E.g. the pathdefining means may comprise three moment arms each comprising a vacuumcup in one end and in the other end the moment arms may be connected tothe same wheel. The latter embodiment may also be provided with twomoment arms or four moment arms or five moment arms or six moment armsor ten moment arms.

The radius of the wheel may be substantially equal to the radius of awindscreen of an automobile. Thus the radii of the wheel and thewindscreen do not necessarily have to be exactly equal but may vary alittle. The radius of the wheel may be substantially equal to the radiusof a corner of a windscreen so that the knife follows the edge of thewindscreen, thus the knife may cut the glue between the windscreen andthe frame of the automobile.

In one embodiment the wheel may be releasably attached to the pathdefining means. Thus it may be possible to remove the wheel and attachanother wheel e.g. a new wheel or a wheel with a different radius or awheel with different surface properties or a wheel with a differentshape. The tool guiding apparatus may further comprise a plurality ofinterchangable wheels at least two of said wheels having differentradii. The apparatus may comprise a plurality of wheels with differentradii, so that a wheel with a radius substantially equal to the radiusof the windscreen may be attached to the path-defining means.

At least a part of the surface of the wheel may comprise a frictionincreasing material. The friction may also be provided by afriction-increasing surface of the wheel. The friction-increasingsurface and/or the friction increasing material may have a coefficientof static friction or a coefficient of dynamic friction of 0.1 or 0.2 or0.3 or 0.4 or 0.5 or 0.6 or 0.7 or 0.8 or 0.9, cf. Engineering Mechanicsvolume 1, Statics, second edition, ISBN 0-471-84911-1, chapter 6 andappendix D.

At least a part of the force transferring element may comprise afriction increasing material. The friction may also be provided by afriction-increasing surface of the wheel. The friction-increasingsurface and/or the friction increasing material may have a coefficientof static friction or a coefficient of dynamic friction of 0.1 or 0.2 or0.3 or 0.4 or 0.5 or 0.6 or 0.7 or 0.8 or 0.9, cf. Engineering Mechanicsvolume 1, Statics, second edition, ISBN 0-471-84911-1, chapter 6 andappendix D.

In one embodiment the surface of the force transferring element and/orthe wheel may comprise a Velcro® material so as to increase the frictionbetween the force transferring element and the wheel. In otherembodiments the friction may be provided by a sticky material such asglue.

The automatic tool actuation means comprises a motor. The motor may bean electric motor such as a DC motor or an AC motor. The motor may insome embodiments be a hydraulic motor or a pneumatic motor or acombustion engine. The motor may be electrical such as a motor whichneeds a power supply of 6 volts or 12 volts or 18 volts or 24 volts or50 volts or 75 volts or 100 volts or 110 volts or 150 volts or 200 voltsor 220 volts or 230 volts or 275 volts or 325 volts or 350 volts or 380volts or 500 volts or 1000 volts. The motor may be able to provide aneffect of 200 watt or 400 watt or 600 watt or 800 watt or 1000 watt or1200 watt or 1400 watt or 1600 watt or 1800 watt or 2000 watt or 2200watt or 2400 watt or 2600 watt or 2800 watt or 3000 watt or 5 kW or 7.5kW or 10 kW or 20 kW. In one embodiment the electrical motor maycomprise a plug for power supply which is adapted to the retrieve powerfrom a moving vehicle such as a car or a truck e.g. the electrical motormay comprise an adapter for the cigarette lighter plug of a car, but itmay also comprise means for retrieve power directly from a battery.

The automatic tool actuation means may be adapted to pull the tool alongthe path, and thus the force transferring element may rolled in on awheel connected to the motor during operation of the apparatus.

The knife may be releasably attached to a fixture e.g. by means ofscrews. The fixture may comprise a means for activating the motor. E.g.so that by pressing a button the motor may be activated. In anotherembodiment the fixture comprises means which detect application ofpressure from the fixture to the knife and upon such detection the motormay be activated. Furthermore, the means for activating the motor may beadapted to control the speed of the motor e.g. the fixture may comprisea button detecting difference in a force applied and upon said detectionthe speed of the motor may be varied. The speed may be constant orchanged in steps or changed continuously.

The means for activating the motor may be wireless e.g. so that a buttonon the fixture is not in wired electrical connection with the motor. Inother embodiments the button may be in wired electrical connection withthe motor.

An apparatus according to the present invention may comprise controlmeans for controlling the speed of the motor. Said means may control thespeed in a predefined pattern e.g. so that the acceleration of the knifenever exceeds a maximum value. Thus it may be possible to start theknife in a slow motion and accelerate the speed. This may improve thequality of the cut made by the knife.

According to a second aspect the invention relates to a method forguiding a tool along a path on a surface to be processed, said methodcomprising the steps of:

attaching at least one path defining means to the surface to beprocessed, and advancing the tool along the path by activating anautomatic tool actuation means.

The path defining means may in one embodiment be attached to a surfaceadjacent to the surface to be processed. The tool may be advancedstepwise but could also be advanced in a continuous movement e.g. sothat the speed is increased slowly until it reaches a desired maximumspeed.

The method may further comprise the step of attaching the automatic toolactuation means to the surface. The path defining means may be attachedprior to attaching the automatic tool actuation means and vice versa.

The invention according to the second aspect of the invention maycomprise any feature or element of the first aspect of the invention.

DETAILED DESCRIPTION OF THE INVENTION

Preferred embodiments of the invention will now be described in detailwith reference to the drawing in which:

FIG. 1 shows an apparatus according to the first aspect of theinvention,

FIG. 2 shows a path defining means according to the invention and

FIG. 3 shows a tool comprising a fixture and a knife according to thepresent invention.

Referring now to FIG. 1, the present invention relates to an apparatus 2for guiding a tool 4 along a path 6. The apparatus is attached to awindscreen 8 which is attached to a car (not shown). The edge 10 of thewindscreen 8 is glued to the car and the tool 4 is used to cut saidglue. The apparatus comprises an automatic actuation means 12 comprisinga motor 14 which is interconnected to a in-rolling-wheel 16 which rollsin a force-transferring element—here a belt 18—during operation of theapparatus 2. The automatic actuation means 12 comprises twopositioning-wheels 20 which position the belt 18 in relation to thein-rolling-wheel 16. Furthermore, the automatic actuation means 12comprises three moment arms 22 each of which is connected to a vacuumcup 24 in a first end and in a second end is connected to the motor 14.The apparatus 2 further comprises two path-defining means 26 each ofwhich comprises a moment arm 22 in one end connected to a vacuum cup 24.In the other end the moment arm 22 is connected to a path-defining wheel28. The wheel-surface 30 of the path-defining wheel 28 is covered withVelcro® tape at the same time the belt-surface 32 is also covered withVelcro® tape. Thus when the belt 18 is rolled in, the Velcro® tapepositions the belt in relation to the wheel so that the belt 18 is notstripped off during operation. Furthermore the path-defining wheel 28comprises flanges 32 which also positions the belt 18 in the axialdirection 34 of the path-defining wheel 28. The belt 18 comprises a hook36 which during operation is attached to the tool 4. The tool 4comprises a button 38 for activating the motor 14. The motor 14comprises a power supply cable 40 which is adapted to be connected tothe cigarette lighter plug of a car by means of a plug 42.

FIG. 2 shows a path-defining means 26 comprising two vacuum cups 24comprising handles 44 which is used to create a vacuum between the abuttom surface 46 and the windscreen 8. Furthermore the path-definingmeans 26 comprises a moment arm 22. In some embodiments the moment arm22 is so long that it is possible to attach the path-defining means 26to a surface of the windscreen which is substantially plane. This isdesirable as it improves the ability of the vacuum cups 24 to maintainthe vacuum. The wheel 28 may be pivotally connected to the moment arm 22around the moment-arm-axis 48. The wheel-surface 30 has a surface whichhas high frictional properties e.g. the surface may be covered withVelcro® tape. Additionally the belt 18 is covered with Velcro® tape. TheVelcro® tape may be provided on one side or on both sides of the belt 18and on a part of the side(s) or on the entire side(s).

FIG. 3. shows the tool 4 comprising fixture 37 having a button 38 whichis used to activate the motor 14. The tool may comprise a wire (notshown) connected to the motor, but may also comprise a transmitter forwireless activation of the motor 14. A knife 50 is attached to thefixture 37 and may be changed if the screws are removed. The tool 4comprises a force transferring arm 54 comprising a hole 56 in which thehook may be inserted.

1. A tool guiding apparatus for guiding a tool along a path on a surfaceto be processed, said apparatus comprising: at least one path-definingmeans adapted to be attached to the surface, automatic tool actuationmeans adapted to advance the tool along the path, wherein the automatictool actuation means comprises a flexible force-transferring elementcomprising a first end and a second end, the first end being attached tothe automatic tool actuation means and the second end being attached tothe tool.
 2. A tool guiding apparatus according to claim 1, wherein thepath-defining means is adapted to engage at least a part of the flexibleforce-transferring element.
 3. A tool guiding apparatus according toclaim 1, wherein the path-defining means comprises a wheel adapted toengage at least a part of the force-transferring element.
 4. A toolguiding apparatus according to claim 1, wherein the automatic toolactuation means is adapted to be attached to the surface.
 5. A toolguiding apparatus according to claim 4, wherein at least one of theautomatic tool actuation means and the at least one path-defining meanscomprises at least one vacuum cup.
 6. A tool guiding apparatus accordingto claim 1, wherein the tool is a knife with a cutting edge.
 7. A toolguiding apparatus according to claim 6, wherein at least a part of thecutting edge extends in a direction transverse to a line defined by atleast a part of the force-transferring element.
 8. A tool guidingapparatus according to claim 5, wherein the vacuum cup and the wheel areinterconnected by a moment arm.
 9. A tool guiding apparatus according toclaim 3, wherein the radius of the wheel is substantially equal to theradius of a windscreen of an automobile.
 10. A tool guiding apparatusaccording to claim 3, wherein the wheel is releasably attached to thepath defining means.
 11. A tool guiding apparatus according to claim 3,further comprising a plurality of interchangeable wheels at least two ofsaid wheels having different radii.
 12. A tool guiding apparatusaccording to claim 5, wherein at least a part of the surface of thewheel comprises a friction increasing material.
 13. A tool guidingapparatus according to claim 5, wherein at least a part of the forcetransferring element comprises a friction increasing material.
 14. Atool guiding apparatus according to claim 1, wherein the automatic toolactuation means comprises a motor.
 15. A tool guiding apparatusaccording to claim 14, wherein the motor is electrical.
 16. A toolguiding apparatus according to claim 1, wherein the automatic toolactuation means are adapted to pull the tool along the path.
 17. A toolguiding apparatus according to claim 6, wherein the knife is releasablyattached to a fixture.
 18. A tool guiding apparatus according to claim6, wherein the fixture comprises a means for activating the motor.
 19. Atool guiding apparatus according to claim 18, wherein the means foractivating the motor is adapted to control the speed of the motor.
 20. Atool guiding apparatus according to claim 18, wherein the means foractivating the motor is wireless.
 21. A tool guiding apparatus accordingto claim 14, further comprising control means for controlling the speedof the motor.
 22. A method for guiding a tool along a path on a surfaceto be processed, said method comprising the steps of: attaching at leastone path defining means to the surface to be processed, and advancingthe tool along the path by activating an automatic tool actuation means.23. A method according to claim 22, further comprising the step ofattaching the automatic tool actuation means to the surface.